1. Field of the Invention
The present invention relates to pleated filter elements for filtering fluids, and more specifically a pleated filter element provided with arrays of elongated embossments arranged in an offset pattern.
2. Description of the Prior Art
Fluid filters are well known devices in which a flow of fluid (such as air, oil, fuel, etc.) is drawn or forced into a housing and caused to pass through a filter media configured to remove dirt, dust and other particles entrained in the fluid flow. The fluid flow cleaned by the filter is thereafter used in devices such as internal combustion engines.
A filter element is disposed in a filter housing between a fluid inlet and a fluid outlet. Generally, a seal is positioned to seal the fluid inlet from the fluid outlet so that all fluid passing out of the outlet has been passed through the filter element. For most automotive applications, the filter element is conventionally constructed of pleated paper with pleats facing upstream toward the fluid stream inlet and downstream toward the fluid stream outlet. These filters may be of the cylindrical, frustoconical or panel configuration. Many light duty air filters used in automotive applications to filter inlet air for internal combustion engines include substantially rectangular filter element panels to filter the high velocity air consumed by the engines. Typically, oil and fuel filters used in automotive applications to filter inlet oil and fuel for internal combustion engines include substantially cylindrical filter elements. Usually, the fluid filters configured of pleated media filter elements have substantially similar pleats.
Currently, there is a need to increase dirt holding capacity of the fluid filters while reducing fluid low restriction. In order to conserve space in engine compartments, panel air filters are now being employed, but panel air filters have encountered the aforementioned problems of reduced dirt holding capacity and relatively high restriction.
Typically, filter elements having pleated filter media include spacer arrangements between panels of the media for filtering particulate bearing fluid streams. However, the spacers tend to be inserted elements which increases the cost of filter media and can compromise the reliability of the filter media. This is because inserted spacers can become dislodged and damage the filter media if on the upstream or dirty side of the filter media. If on the clean side of the filter media, the spacers can become dislodged and possibly damage the machinery served by the filter media.
Therefore, a need exists to develop improved pleated fluid filter elements with increased dirt holding capacity and reduced fluid low restriction that advance the art.